infusion media questions

Discussion in 'Materials' started by JohnMarc, Feb 14, 2020.

  1. JohnMarc
    Joined: Feb 2018
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    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    Thanks for coming back to me, my layup consists of
    1 x 195 gsm Twill weave,
    2x 410gsm _+45,
    Peel ply
    Although it is the amount of resin I should be allowing for for the mesh or flow media that is puzzling me, it doesn't make sense to me that I am allowing about double the amount of resin just for the flow media.......
     
  2. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    i think you are reading the rate for a mesh that stays in the core... it is notable you did not include the mesh in the stack; so I assume itnos external

    You can easily verify my assumptions by measuring the thickness of the mesh and backing out the percent of the mesh that is actually mesh.

    I am not your infusion expert on the site. Just offering a wee bit of help hoping others will jump in.

    I suppose it is also worth noting; you may not have a suitable mesh.
     
  3. JohnMarc
    Joined: Feb 2018
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    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    My understanding of the process is a wee bit further down the road than it was when I first started with another post almost two years ago although I am still very much a beginner and am always keen to learn from my mistakes, of which there have been plenty ......
    the flow mesh effectively facilitates the flow of the resin while under vacuum, (hence me excluding it from my stack) and once it has cured we then remove the mesh etc down to the peel ply level. I am just amazed as to the quantity of "additional" resin that I apparently have to include in my calculations to accommodate the flow mesh. So as such the stack is almost irrelevant to my question, I am just wondering of anyone out there agrees to the recommended 700g per M2 I need to add to my resin amount purely because of the flow medium? I am only questioning it because it would almost double my amount of epoxy......
     
  4. fallguy
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    fallguy Senior Member

    You did not listen well.

    If the mesh is left in the stack, how much resin is required? You must answer this question or contact the vendor for guidance on the 700g. I am taking a wild guess that 700g is if left in. Capiche?

    What is the resin content for the peelply? That also needs to drink.

    Also, is the flow media the top of the stack? Isn't it going to have plastic bagging pushing on it?

    Sorry if I sound harsh, it happens when I am ill.
     
  5. JohnMarc
    Joined: Feb 2018
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    JohnMarc <--- My ultimate goal

    Ha Ha would love to get hold of the vendor...... they all be closed thanks to some nasty bug doing the rounds....... yes good point the peel ply and the feeder pipes etc. get an extra 100 grammes.....
    I think you are right insofar as to allowing an amount to be left behind...... it has a "springy" texture exactly to maintain the resin flow under the pressure of the bagging material,,,,, so wether you be harsh or a wee bit grumpy (I trust you'll get better soon) me thinks between the two of us and our limited knowledge of the process ('specially mine) we have solved the conundrum..... it would appear it is indeed for the resin left behind in the flow medium......
    I can sleep peacefully now before I do the infusion in the morning.
    Many thanks for the exchange .... and I trust you will feel better soon
     
  6. fallguy
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    fallguy Senior Member

    Just be sure to use plenty of resin on your first run. If you throw out a bit; measure the amount so you can tweak another run.
     
  7. AndrewK
    Joined: Mar 2007
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    AndrewK Senior Member

    700gsm for the flow mesh sounds correct, use perforated infusion release film under the mesh.
    For thin laminates you don't need such a fast (high volume) media, I use 30% shade cloth much cheaper and consumes 320gsm resin.
    Infusing stitched glass at full vacuum at sea level use 50% of glass weight, carbon will be different due to density. Infusion is about filling the void volume.
    I use a spreadsheet that calculates the resin required for each infusion, if you don't know exactly how much you need then mix a bit extra but clamp off the inlet when the resin front is ~50mm away from the finish.
    Have your resin bucket 300-500 mm below the job. Also have a large resin break between the job edge and the vacuum lines.
     
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  8. fallguy
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    fallguy Senior Member

    good to hear from an expert! Can you explain the resin break a bit more? Is this the area you intend to flow at the end before shutting off flow? What is large? 12" or 24"
     
  9. JohnMarc
    Joined: Feb 2018
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    JohnMarc <--- My ultimate goal

    Thanks Andrew for responding..... so the question I have is this, does the perforated infusion release film actually replace peel ply? I am using 3mm Mycell 80 in the layup (I will naturally include that in the calc's for the resin amount) but the reason I mention it is that it will require a good flow of resin...... does the release film restrict the flow more than the peel ply or am I over thinking it?
    Yes agreed I hear you about the resin break, only hesitation I have there is I have had an issue previously where the vacuum bag created an almost perfect seal against the mould almost shutting down the flow entirely. I am trying to find some info on the net regarding the resin break and wether I should include flow media or anything else to keep it "open" for the air/vacuum flow.
    Safe safe
     
  10. AndrewK
    Joined: Mar 2007
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    AndrewK Senior Member

    12" resin break is good, with this amount along with clamping off the resin inlet before the resin front reaches the edge of the job will save you from cleaning out your catch pot and also allow you to reuse the vacuum lines.
    You must have at least one layer of peel ply connecting your job and the vacuum line, but avoid high volume like the flow mesh like I have seen some people use.
    At times you can not avoid placing your vacuum line right at the end of the job, but when ever I have room I will have the peel ply over size by 500mm place my vacuum spiral ~100mm from PP edge and then fold back PP over the spiral.
    I only use 4mm micro irrigation tubing and connectors for the vacuum, 8mm spiral for vacuum and resin distribution, 8mm tubing for resin inlets.

    Release film does not replace peel ply. Does it restrict resin flow more than peel ply? good question, don't have an answer. But can say that flow is good enough, as long it is film for infusion and not the one intended for bagging alone.
    The weight of your finished article should not be weight critical, instead of 3mm pvc core I would instead use infusion core that can do the job of both flow media and the core, like Soric and other cheaper alternatives.
    Even consider continuous filament matt, I have used this but not Soric. Lantor Soric does look like a good product.
    Andrew
     
  11. JohnMarc
    Joined: Feb 2018
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    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    Hi Andrew
    I don't know if you have seen my pics at the beginning of this post but my mould flanges are not as big as I would like it to be to afford a very big resin break .....but thanks for the advice re peel ply to keep it open.
    As regards the core material I have already infused the hatch using carbon fibre with the 3mm Mycell (I'll attach a Piccie of the hatch and the hatch within the mould ready for the final infusion) and if I say so myself it worked pretty well.
    If I understand it correctly I can use the release film between the flow mesh and the peel ply..... but I am not too sure I want to risk using an unfamiliar method on this particular infusion..... (due to the lockdown all the suppliers are closed so have to get it right first time without the luxury of a test run......)
    IMG_9799.jpeg IMG_9801.jpeg IMG_9802.jpeg IMG_9807.jpeg

    I am a little concerned about maintaining the flow over the edge of my flange (the pencil "bit chewed by my dog....." is to give an idea of size) so thinking of tacking some extra flow media on the resin side to "blunt" the corner a bit....
     
  12. AndrewK
    Joined: Mar 2007
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    AndrewK Senior Member

    Your job when trimmed is the white bit? blue gets cut off?
    Looked at your earlier pics, you gave up on the bead?
    Where the pencil is pointing is the resin inlet side, vacuum line opposite end?
     
  13. JohnMarc
    Joined: Feb 2018
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    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    Nope the bead is there...... wee bit different to the drawing .... the blue is an additional layer of gelcoat I added on top of the flange to ensure a good seal for the vac tape....although the gelcoat also went into the bead area...... pencil pointing to bead...... in any rate I did the layup...... gelcoat first with hatch in place so gelcoat looks a bit messy on the hatch but will cut it out for the opening...... it all seemed to go well.....in fact I have left the vacuum running ...... trust you can make sense of attached pic but followed your advice on the break ...... went with the Mycell...... had a good flow of resin..... got the volume spot on.... had 30 g left in pot..... so all in all good so far.....thanks for your help.....
    although mmmm all will be revealed with remoulding...... IMG_9809.jpg
     
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  14. AndrewK
    Joined: Mar 2007
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    AndrewK Senior Member

    Well done, looks like the infusion went well for you, perhaps one small area not wet out right at the edge at the vacuum line (white spot).
    Did you perforate the core, I can not see it in the photo.
     

  15. JohnMarc
    Joined: Feb 2018
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    Location: Knysna South Africa

    JohnMarc <--- My ultimate goal

    Well spotted..... photo taken during the process.....I had of course at this stage switched the resin off and was watching that spot disappear ..... it was the last place to fill.........
    Yes I did indeed perforate the core....... lots of drilling....
    Will report back after demoulding .........
     
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